The object of the invention is a valve unit for initial filling of near-vertical angular transport channels with mass flow in the transfer systems of rod like articles used in the tobacco industry.
In the production lines of rod like articles of the tobacco industry, such as cigarettes, filters or cigarettes with the filter already stuck on, in the course of the production process said products cover a considerable distance after leaving the manufacturing machine before they are placed into packages in the packaging machine or into the stores. They are usually conveyed in a multilayered ordered stack, which eliminates the deformation or damages. There is a need of handling the stream of articles for the purpose of delivering to or from different devices used in the production line. For this purpose, on the path of horizontal conveyors transferring the products, near-vertical angular channels connecting one horizontal conveyor or hopper with another horizontal conveyor or a receiving device are formed. Rod like articles completely fill the near-vertical angular channels and principally horizontal conveyors, which is a condition determining the preservation of their arrangement. The transfer on a horizontal path is usually forced, whereas the transfer in angularly situated channels is usually effected by gravity. Said handling of the flow many times consists in cutting off the angular channel in which the articles flow or in directing the stream of articles to another receiving device, with the necessary condition being that the rod like articles are as little damaged as possible when handling the flow. An important problem to be solved is gentle feeding of a stack of articles into the earlier emptied angular channel, for instance in case of a change of the range of articles, so that they are not damaged. In order to achieve the said aim, initial filling of the angular channel is frequently carried out by hand, using a blocking element placed earlier into the channel. In the description of the U.S. Pat. No. 6,540,061 a method and an apparatus for transporting cigarettes are presented; in one of the embodiments thereof, shown in FIG. 10 of the drawing, a vertical channel connecting an upper horizontal conveyor with a lower horizontal conveyor was disclosed. Next to the channel, a guide is disposed on which a trolley guiding a plate closing the inside diameter of the channel moves. Before the commencement of filling of the channel with rod like articles, the plate is situated at the end of the upper horizontal conveyor close to a filling sensor. A signal from the sensor indicating that the upper conveyor is filled causes the activation of the trolley, and the plate moves down the channel, holding the front face of the mass flow. After reaching the lower horizontal conveyor, the plate is deflected so that it constitutes a fragment of an upper wall of said conveyor and does not hinder continued movement of the mass flow on the lower conveyor. If the sensor disposed in the lower conveyor detects the absence of mass flow, the plate is again inserted into the inside diameter of the lower conveyor and transferred by the activated trolley as far as the upper conveyor where it waits for the front face of the mass flow. On the other hand, in the description of the application for the European Patent no. EP 1.704.787 a method and an apparatus to control the filling of cigarette feeding channels, in particular during the first filling of the packaging machine, was disclosed. The apparatus has two angularly situated channels, each of which is provided with a guiding member slidably mounted in a side wall of the channel. In the bottom part of said wall a niche is situated which can contain the guiding member, after earlier turning, in order to fully open the channel. In the course of the first filling the member moves down, holding the front face of the mass flow of cigarettes, and at the final stage hides in the niche, whereas its role in the further part of the channel is taken over by flexible members. A slightly different solution was presented in the description of the U.S. Pat. No. 4,572,352 where the angular channel connecting un upper horizontal conveyor with a lower horizontal conveyor is closed with a flexible valve element which under the pressure of rod like articles flowing in the upper conveyor progressively takes the shape of an angular channel, facilitating gentle feeding of the articles into the lower conveyor.